1. Field of the Invention
The present invention relates to a connector for use with communications devices, and more particularly to a plug-in multiple-pin connector for use on the rear end of a package to be inserted into a bookshelf-type unit.
2. Description of the Related Art
Bookshelf-type units have a pair of upper and lower panels with a plurality of upper and lower guide rails mounted on the inner surfaces thereof and a backboard extending between the upper and lower panels. A plug-in multiple-pin connector for use with such a bookshelf-type unit comprises a plug mounted on the backboard and a socket mounted on the rear end of a package supporting an electronic circuit. The package is inserted into the book-shelf-type unit with the upper and lower edges of the package being guided along upper and lower guide rails until the socket is electrically connected to the plug. When a plurality of packages are inserted into the bookshelf-type unit, the packages jointly make up a communications device.
FIGS. 1 and 2 of the accompanying drawings shows one such conventional plug-in multiple-pin connector for use with a bookshelf-type unit.
As shown in FIG. 1, bookshelf-type unit 51 has backboard 52 positioned on the back of the unit and supporting a plurality of plugs 56. Package 53 with an electronic circuit thereon has socket 54 on its rear end. Package 53 is inserted into bookshelf-type unit 51 along selected upper and lower guide rails 55 on upper and lower panels of bookshelf-type unit 51. The distance between the bottoms of the guide grooves in upper and lower guide rails 55 is slightly larger than the vertical dimension of package 53, so that package 53 is slightly loose vertically in guide rails 55 when socket 54 is inserted into plug 56.
As shown in FIG. 2, when socket 54 is fitted into plug 56, socket 54 is guided by beveled edges 56b on the open end of box-shaped insulative casing 56a of plug 56. Socket 54 has a plurality of contact insertion holes 54a each with beveled surfaces 54b at their open ends. As socket 54 is inserted into plug 56, pins 56c of plug 56 are each guided by beveled surfaces 54b and inserted into contact insertion holes 54a until pins 56c are each electrically connected to socket elements 54c.
The conventional plug-in multiple-pin connector suffers from the following two drawbacks:
Recently, there is a demand for more pins per connector and smaller connector sizes to achieve higher packaging density. It is therefore necessary to reduce pin-to-pin spacing and pin diameter. If a package with a plug-in multiple-pin connector designed to meet those requirements is inserted quickly into a bookshelf-type unit, then when the pins strike the beveled surfaces of the contact insertion holes, the pins tend to buckle due to their low mechanical strength, and fail to fit well into the contact insertion holes.
Inasmuch as the pins are slender, they are highly likely to bend under external force, particularly when they are improperly handled while multiple-pin connectors are being fabricated. The small pin-to-pin spacing requires contact insertion holes to have smaller beveled surfaces, making it necessary for the pins to have a minimum degree of bending tolerance. The strict pin tolerance greatly affects both the yield of multiple-pin connectors and the electric connection reliability of the connectors.